Need help with my Magellan Explorist 500

Like the title says I have a Magellan Explorist 500. I'm trying to load the Morth Cumberland and Picket Trail maps on to it but I'm not having any luck. It has a new 8gb SD card in it for storage. If I try to import the map from the Google Earth page it says it can't find the gps unit. If I load the maps directly onto the SD card I can find the file names on the gps unit but there is nothing in them. Anyone have any suggestions or maybe directions on how to get these loaded up? Thanks in advance!

If I trade I'll definetely go with a garmin. Seems like they are a little more user friendly. My Explorist is easy to use by itself, but has been a nightmare to try and upload anything on. I've tried all the software you guys have suggested plus the MapSend that came with the unit. Can't get anything to work. Its like the unit isn't reading the SD card or any of the files so I can't access any of the info. Oh well...I got a birthday coming up in a little over a month so I may start hinting about a new GPS. lol.

Fixed the issue with my Magellan unit...I just got my new Garmin Rino 530HCx. lol!!! Now I just have to learn how to work it. Looks like a really nice unit with lots of useful features. Excited to get out and work with it!

The new Rino 530 was the fix. I never did get anything to load onto the Explorist. Nor could I manipulate any of the tracks or points I had on it with any of the software. I may have been missing some program since I bought it used. Not sure what the problem was. It seems that the Garmin units are more user friendly, and there is also alot more support (both factory and on forums such as this one) for the Garmins. I usually carry both a radio and a gps so with the Rino I can reduce clutter on my handlebars, and it has alot of nice features(NOAA weather channels, ascent/decent recorder, expandable memory just to name a few) so that is why I picked this particular model.